Metal composite plate or strip refers to a plate or strip by compositing another metal plate or strip onto a layer of metal to achieve the effect of resource saving and cost reduction without reducing the effect in use (anti-corrosion performance, mechanical strength, etc.). With the technology of metal composite material, the respective advantage of each of constituent element material can be exerted, to achieve optimum allocation of each of constituent element material, save valuable metallic material, achieve required performance which the single metal cannot meet. Metal composite plate or strip is mainly used in various industries such as anti-corrosion, pressure vessel manufacture, electricity build, petrification, pharmaceuticals, light industry and automobile etc. For the compositing method, generally there are compositing method by explosion and compositing method by metal pressure processing.
The compositing method by explosion involves compactly welding the dissimilar metal plates together by using the high energy produced by explosion, which can achieve the composition of metals which have a great difference in performance and has the strong interface binding force. However the composite by this method has smaller size and poor shape and lower yield. Furthermore, the high energy impact of explosion affects metal structure and greatly influences the environmental pollution.
The compositing method by pressure processing refers to that the distance of contact surfaces of dissimilar metals affected by deforming force during plastic deformation approaches to the thick of an atom to form a number of bonding point, so as to diffuse to form steady metallurgical bonding. Process for slab and interface compositing mechanism are main factors constraining the quality and yield of composite metal plate/strip. Rolling compositing is the most studied method among pressure processing method, comprising hot rolling, cold rolling, non-isothermal rolling and asymmetrical rolling etc. However rolling has lower compositing energy, there is great difference of material mechanical property between dissimilar metals. The bonding interface is more complex than that in explosion compositing, wherein a bonding surface of composite slab by casting may easily produce bubble and lard crack and so on. Selection of the brazing flux for brazing compositing slab greatly affects the interface bonding of different metals and results in cracking. So how to get steady interface bonding of dissimilar metals, high quality precision, broad product scope, and high compositing efficiency are the urgent problems to be solved.